DC Load Regulation and AC Ripple
PSU Testing Methodology
Establishing an accurate load is critical to testing and evaluating a PC power supply. PCPerspective’s power supply test bench can place a precise DC load on the PSU under test. Each power supply is tested under controlled, demanding conditions up to its maximum rated load (at 40ºC). Our current suite of tests includes:
• DC Load Regulation
• AC Ripple and Noise
• Efficiency
• Differential Temperature
• Noise
The Seasonic PRIME Ultra 850W Titanium power supply was evaluated on both features and performance. A full range of equipment was used to test the power supply under controlled load conditions.
• (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
• (4) CSI3711A Programmable DC load (+12V)
• (3) 218W Precision resistor load bank (+12V)
• Switchable precision resistor load bank (-12V and +5VSB)
• Agilent 34401A digital multimeter (Accuracy ±0.0035% vDC)
• Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
• DS1M12 "StingRay" digital oscilloscope (20M S/s with 12 Bit ADC)
• Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC
• Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)
The following cables/connectors were used to connect the Prime Ultra Titanium power supply to the PCPerspective power supply test equipment.
• (1) 20+4 pin ATX
• (2) 8-pin EPS/ATX12V
• (6) 6-pin PCI-E
• (6) SATA
• (3) Molex
DC Output Load Regulation
To simulate demanding and maximum loading conditions, the power supply was connected to the load testers and supplied with a constant 120 VAC. In this test we are interested in seeing how well a PSU can maintain the various output voltages while operating under different loads.
The ATX12V V2.2 tolerance for voltages states how much each output (rail) is allowed to fluctuate and has tighter tolerances now for the +12V outputs. I have also included a second table of expanded tolerances (±1% to ±6%) for reference.
The following tables list the DC voltage results for the three PSUs while operating on 120 VAC, 60 Hz.
The PRIME Ultra 850W Titanium power supply produced outstanding voltage regulation on all of the DC outputs while delivering the full rated load. And the three primary rails stayed within the claimed 0.5% load regulation!
AC Ripple and Noise on the DC Outputs
The amount of AC ripple and noise present on the DC outputs was checked using a digital oscilloscope. This AC component may be present in the KHz range where most switching power supplies operate or it may be more prevalent at the 60 Hz line frequency. We adjust the O-scope time base to look for AC ripple at both low and high frequencies. The ATX12V V2.2 specification for DC output noise/ripple is defined in the ATX12V Power Supply Design Guide.
Ideally we would like to see no AC ripple (repetitive) or noise (random) on the DC outputs – the cleaner the better! But in reality there will always be some present. I measured the amplitude of the AC signal (in millivolts, peak-to-peak) to see how well the power supply complied with the ATX standard. The following table lists the ripple/noise results during all of the load tests for the main output voltages of interest.
Again, the PRIME Ultra 850W Titanium power supply exhibited excellent AC ripple and noise suppression across the full range of loads.
Nice Review. I always enjoy
Nice Review. I always enjoy the details. : )
One question though. Are there any companies that are selling PSU’s in the 700-900 Watt range, that have a better efficiency than Titanium ?
Dell was supposedly the first to get Titanium on the market, but I was wondering if there’s a company that has been bold, and put a product that is beyond Titanium+ ?
Personally, I want the most efficient PSU possible, because of high room temps, due to climate of my country.
Thank you – we are glad you
Thank you – we are glad you enjoy the reviews! Currently, within the 80 Plus Orginaization certification criteria, Titanium is the highest rating. Keep in mind that this is a minimum specification and a vendor can always produce a product that exceeds the criteria (even better efficiency). For example, if Seasonic came out with a new Super Ultra PSU that achieved 98% efficiency it would still be labelled a Titanium unit.
Thanks for the response Lee.
Thanks for the response Lee. : )
Do you know of any PSU’s that meet the criteria that you mentioned ?
I thought you would be best to ask, because your company probably sees tons of titanium PSU’s, and maybe you remember the literally best % efficiency PSU.
I would be very interested in buying a PSU that exceeds Titanium Standards.
If you can’t remember any, that’s alright, Titanium is great for now, but I’m always looking for better.
I have high temperatures where my PC sits, so every % point of efficiency, makes a big difference to me.
No, I am not aware of any ATX
No, I am not aware of any ATX PSUs that operate up to 98% efficiency – sorry. Most of the "Titanium" series PSUs I have tested in the last year peak at about 94% efficiency.
If you really want to optomize the efficiency of your PC, make sure you match the PSU to the actual load your PC is pulling. For example in this review, the efficiency of the PRIME Ultra 850W Titanium peaks at about 60% load. Ideally you should measure the actual load of your PC with an inexpensive AC watt meter and then select a PSU that has a peak efficiency around that load. An 850W PSU would be ideal for a PC that draws 450~550W. Hope this helps.
Cooler Masters Made in Japan
Cooler Masters Made in Japan 1200W unit exceeds Titanium standards.
That being said, why do you need such high efficiency? 80 Plus ratings are a scam and youre better off with a bronze unit thats high quality than some arbitrarily 80 plus titanium rated thing.
Ya why would anyone want to
Ya why would anyone want to know what efficiency to expect with a shiny marketing sticker. I mean like c’mon the bronze is good enough for gaming right but it is just arbitrary anyways. Who cares I can get a 300W supply for like 15 bucks 80 plus standards are such a sham.
How long is a power supply
How long is a power supply run at say, 450w to test the temperature of air coming out and noise?
We test a PSU for 30 minutes
We test a PSU for 30 minutes at each load point to let temperatures equilibrate.
I bought a Prime Titanium 650
I bought a Prime Titanium 650 about 8 months ago. What makes this new model any different?
For example, it says: “The PRIME Ultra Series builds upon the PRIME Titanium platform by delivering extremely tight voltage regulation on the three primary rails (+3.3V, +5V and +12V) and providing superior AC ripple and noise suppression with an extended hold-up time.”
Does that mean the Ultra has better voltage regulation, AC ripple and noise suppression? They’re both Titanium rated, so should have the same basic specs.
Then we get this “informative” blurb: “This leading member of the series boasts an improved DC to DC converter design where pins and a copper plate replace cables to connect the back panel and the PCB for increased efficiency.”
Does that mean the original Prime DOESN’T have pins and a copper plate?
The packaging looks exactly the same as the one I got, and there is no Ultra marking on the box.
Help me out here…
From their website: ‘Each
From their website: ‘Each PRIME Ultra Series power supply will also ship with a SATA 3.3 adapter to support the “Power Disable” (PWDIS) feature of the newer, high-capacity hard drives. The inline capacitors on the cables were removed, which takes away the bulkiness inside the system. To maximize flexibility, the 180-degree SATA connectors ensuring more flexibility and easier installation.’
The new “Ultra” series
The new "Ultra" series incorporates minor tweaks to the basic PRIME Titanium platform. The features the reader above pointed out are the most obvious external differences. Internally the new Ultra series appears virtually identical – Seasonic doesn't say what minor tweaks they may have made to the circuit design, but I'm guessing they are minor as the PRIME Titanium was already a VERY GOOD platform. I believe the earlier PRIME Titanium units (without the Ultra name) also had the pins & plate. Seasonic is just pointing this out as an included feature. If you have a PRIME Titanium PSU you don't need to worry about missing out on any big improvements. As far as basic performance parameters, I have seen no real difference between the original PRIME Titanium and the new Ultra models: same great efficiency, voltage regulation, AC ripple suppression, etc.!